Steering mechanism comprising a pressure relief valve for damping the end position and protecting the pump from being overloaded

Abstract

The invention relates to a steering device for vehicles with a double-acting hydraulic working cylinder, which is divided into two working chambers by a piston, which is displaceably mounted in the working cylinder, to pivot at least one vehicle wheel, and a pressurizing means device producing a volume flow of a hydraulic medium, the hydraulic medium being supplied to a rotary slide valve, which supplies the volume flow, depending on the rotary slide valve position, to the working chambers of the double-acting hydraulic working cylinder or to a reservoir for the hydraulic medium, wherein when a certain pressure is exceeded in the feed line to the rotary slide valve, a pressure relief valve guides at least a part of the total volume flow of the hydraulic medium past the rotary slide valve in particular to the reservoir.

1 . Steering device for vehicles with a double-acting hydraulic working cylinder, which is divided into two working chambers by a piston, which is displaceably mounted in the working cylinder, to pivot at least one vehicle wheel, and a pressurizing means device producing a volume flow (Q total ) if a hydraulic medium, the hydraulic medium being supplied to a rotary slide valve, which supplies the volume flow, depending on the rotary slide valve position, to the working chambers of the double-acting hydraulic working cylinder or to a reservoir for the hydraulic medium, wherein when a certain pressure is exceeded in the feed line to the rotary slide valve, a pressure relief valve guides at least a part of the total volume flow of the hydraulic medium past the rotary slide valve in particular to the reservoir. 
   
   
       2 . The steering device according to  claim 1 , wherein the pressure relief valve is connected in parallel to a proportional valve of a speed-dependent steering device. 
   
   
       3 . The steering device according to  claim 2 , wherein the proportional valve is closed in the parking region of the speed-dependent steering device and the partial volume flow of the hydraulic medium, which is branched off via the pressure relief valve, arrives at least partly via a connecting line at a reaction device to produce an additional hand torque, before the branched-off volume flow arrives in the reservoir. 
   
   
       4 . The steering device according to  claim 3 , wherein a pressure-controlled control gate valve is connected in parallel to the reaction device. 
   
   
       5 . The steering device according to  claim 1 , wherein the pressure relief valve opens from a certain pressure, in particular from a pressure of 120 bar. 
   
   
       6 . The steering device according to  claim 1 , wherein the pressure relief valve opens at a pressure which adjusts in the feed line, which adjusts at the end stop of the steered vehicle wheels in the feed line to the rotary slide valve.